/ Dictionary / Index U uranium hexafluoride: Meaning and Definition of Find definitions for: ura'nium hexafluor'ide Pronunciation: [key] — Chem. Chem. a colorless, water-insoluble, crystalline, volatile solid, UF, used in its gaseous state in separating uranium 235 from uranium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. uranium dioxide uranium oxide Related Content Daily Word Quiz: effervescent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language